Suresh
K. Mukherji,
Allergic
Fungal
CT Findings1
MD
Ramon
E. Figueroa,
MD
Lawrence
E. Ginsberg,
MD
Barbara
Bradley
A. Zeifer,
F. Marple,
MD
MD
John G. Alley, MD
Laura 1. Cooper,
MD
William
R. Nemzek,
MD
David
Kim
M. Yousem,
R. Jones,
Stephen
Maurido
PURPOSE:
To determine
allergic fungal sinusitis.
MD
Index terms:
Anaphylaxis
and allergy,
23.63
MD
23.205,
sinuses,
Sinusitis,
23.205,
Radiology
1998;
CT, 23.1 2111
23.25, 23.63
207:41
7-422
1 From
the Departments
of Radiology
(5KM., J.G.A., M.C.), Surgery (S.K.M.),
Pathology
(L.L.C.), and Otolaryngology (K.R.J.), University of North Carolina School
of Medicine,
3324 Old
Infirmary
CB
751 0,
Chapel
tomographic
(CT) findings
in patients
with
RESULTS:
Allergic
fungal
sinusitis
was more common
in male patients
and in
patients
aged 20-30
years. All patients
had increased
intrasinus
attenuation
at
non-contrast
material-enhanced
CT. Multiple
sinus involvement
occurred
in 43
patients.
Bilateral involvement
was more common
than unilateral
disease. Forty-four
patients
had complete
opacification
of at least one of the involved
sinuses; 43 of
these patients had expansion
of an involved
sinus, 42 had remodeling
and thinning
of the bony sinus walls, and 41 had erosion of the sinus wall.
23.205
Paranasal
the computed
MATERIALS
AND METhODS:
The authors retrospectively
reviewed
CT scans and
surgical and histopathologic
reports in 45 patients (27 male, 1 8 female; age range,
8-68
years) with allergic fungal sinusitis from multiple
institutions.
The median age
(25 years) and demographics
of the patients were determined.
Two head and neck
radiologists
together
evaluated
the CT scans for the presence
of intrasinus
highattenuation
areas, extent of sinus involvement,
bone expansion
and thinning,
bone
erosion, and extension
of disease into the adjacent soft tissues.
MD
B. Kupferberg,
Castillo,
MD
Aspergillosis,
Sinusitis:
Hill,
CONCLUSION:
Allergic fungal sinusitis is a distinct
clinical entity with nonspecific
symptoms
that may be initially suggested
by the CT findings.
These findings
should
alert the clinician to the possibility
of allergic
fungal
sinusitis and prompt
other
diagnostic studies to establish the diagnosis and treatment plan.
NC
27599-751
0; the Departments
of Radiology(R.EF)andOtolaryngology(S.B.K.),
Medical College of Georgia, Augusta;
the Department
of Radiology,
M.D.
Anderson
Cancer
Center,
Tex (LEG.); the Department
ogy, New York Eye and Ear
Beth Israel Medical Center,
(B.A.Z.);
the Department
of
laryngology,
University
oflexas
Houston,
of RadiolInfirmary,
New York
OtorhinoSouth-
westem Medical Center, Dallas (B.F.M.);
the Department
of Radiology,
University of California
at Davis, Sacramento
(W.R.N.);
and the Department
of Radiology, Hospital
of the University
of
Pennsylvania,
Philadelphia
(D.M.Y.). Received
Sep 19, 1997; revision requested
Oct 22; final revision
received
Dec 31;
accepted
Jan 15, 1998. Address reprint
requests
to S.K.M.
Author contributions:
Guarantor
of integrity of entire study,
S.K.M.;
study concepts
and design,
S.K.M.;
definition
of intellectual
content, S.K.M.; literature research, S.K.M.;
clinical studies,
S.K.M.,
R.E.F., LE.G.,
B.A.Z.,
B.F.M., J.G.A., LL.C., W.R.N.,
D.M.Y., K.R.J., S.B.K., MC.; data acquisition and analysis,
S.K.M.; statistical
analysis, S.K.M.; manuscript
preparation and review, S.K.M., R.E.F., LE.G.,
B.A.Z.,
B.F.M., J.G.A., LL.C., W.R.N.,
D.M.Y., K.R.J., S.B.K., M.C.
Allergic
fungal
fungal
fungal
sinusitis
is a clinical
entity
now thought
to be the most
common
form of
sinusitis
(1,2).
Despite
this, allergic
fungal
sinusitis
is the least understood
form of
sinusitis
and may be underdiagnosed
because
it remains
unfamiliar
to otolaryngologists, pathologists,
and
radiologists
(3). Accurate
diagnosis
is important
because
the
treatment
of allergic
fungal
sinusitis
is substantially
different
from
that of other
types
of
fungal
sinusitis
(1,4).
In the most
recent
classification
system
(1), fungal
sinusitis
is divided
into invasive
and
noninvasive
forms.
Patients
with
invasive
fungal
sinusitis
typically
have
acute
onset
of
fever,
cough,
nasal
mucosal
ulceration
individuals
are usually
immunocompromised.
mellitus,
The
severe
malnutrition,
most
recent
classification
and
or
malignancy
scheme
lists
eschams,
epistaxis,
and
Associated
conditions
that results
the following
headache.
include
in severe
neutmopenia.
categories
of invasive
Affected
diabetes
fungal
sinusitis.
Acute
(fulminant)
fungal
sinusitis
is characterized
histologically
by invasion
of the
mucosa,
submucosa,
or blood
vessels
by fungal
hyphae.
The most common
organisms
are
of the order Mucomales
and the genus
and species
Aspergillus
fiunigatus.
Patients
with acute
fungal
sinusitis
require
radical
d#{233}bnidement,
antifungal
therapy,
and treatment
of the
underlying
condition
(1).
Granubomatous
invasive
fungal
sinusitis
(“indolent
fungal
sinusitis”)
is a rare condition
that has been reported
primarily
in Africa and Southeast
Asia, with scattered
reports
in the
United
States.
The disease
is characterized
by profuse
fungab
growth
in the paranasab
sinuses
and regional
tissue
invasion.
A fiimigatus
is the most commonly
isolated
organism.
Affected
individuals
appear
to be immunocompetent,
unlike
individuals
with
acute
invasive
fungal
sinusitis.
Histologic
examination
reveals
noncaseating
granulomas
with
giant cells and plasma
cells. Treatment
consists
of surgical
d#{233}bnidement and the administration
of itraconazole
(1).
417
Chronic
characterized
The
invasive
fungal
sinusitis
is
by a more prolonged
course.
disease
is typically
associated
with
orbital apex syndrome
owing
to intraorbitab extension
of disease
from the ethmoid sinus. The most commonly
isolated
organism
is Aspergillus
flavus. These patients are usually
immunocompromised
and require treatment
similar to that of
patients
with acute invasive
sinusitis
(1).
with
Patients
fungal
noninvasive
sinusitis
present with chronic
sinusitis
that has failed
to respond to prior medical
or surgical treatment. The forms of noninvasive
fungal
sinusitis
are categorized
as the following.
Mycetoma
is characterized
histobogicabby by a dense accumulation
of fungal
elements
in a mucoid
matrix.
A fumigatus
and the dematiaceous
fungi
are the most
commonly
isolated organisms.
Mycetomas
most frequently
arise in the maxifiary
sinus
and may occur in assodation
with a chronically diseased sinus or polyps (1).
Allergic
fungab
sinusitis
is a disease
of
young
lection
adults
that
for warm
has
a geographic
predi-
and humid
climates.
The disease is characterized
by the presence
of allergic
mucin
within
the
involved
sinus. At endoscopy,
allergic
muon is a brown
or greenish-black
material
that has the consistency
of cottage cheese.
Histologically,
it is composed
of laminated
accumulations
erating
of intact
eosinophils,
tabs, cellular
and
degen-
Charcot-Leyden
debris,
and
hyphae
crys(1).
The diagnostic
criteria
for allergic fungal sinusitis
have recently
been updated:
(a) the presence
of allergic
mucin
at endoscopy; (b) the identification
of fungal hyphae within
allergic
mucin;
(c) the absence of fungal
invasion
of submucosa,
blood vessels, or bone; (d) the absence
of
diabetes
mellitus,
immunodeficiency
disease,
or recent
treatment
with
immunode-
ficiency
drugs; and (e) radiologic
confirmation
(1). In the past,
the imaging
findings
of allergic
fungal
sinusitis
were
grouped
together
with
those
of other
forms of fungal
sinusitis
(5). Findings
of
several
small
series
have
suggested
that
imaging
studies
may help to identify
patients with
allergic
fungal
sinusitis
and
should
(2,3,6-8).
be a part of the diagnostic
criteria
The purpose
of our study was to
reviewthe
computedtomographic(CF)
find-
ings in patients with surgically proved ailergic fungal sinusitis
in an attempt
to determine characteristics
suggestive
of the entity.
MATERIALS
AND
METHODS
We retrospectively
reviewed
surgical and histopathobogic
418
Radiology
#{149}
May1998
#{149}
CT scans and
reports in 45
patients
(27 male,
18 female;
median
age,
CT Findings
Sinusitis
25 years;
mean
age,
8-68 years at initial
27.8 years;
age range,
CT evaluation)
with
sinusitis.
Diagnosis
of aller-
allergic fungal
gic fungal sinusitis
in our series
No. of
of an
allergic
history
at
hanced
bone
CT
non-contrast
studies
material-en-
reconstructed
with
and soft-tissue
algorithms.
Axial
views were reviewed
when available.
The
section thickness
was 3-5 mm.
The CT findings
in 35 of the patients
were reviewed
together
by two head and
neck radiologists.
The CT findings
in the
remaining
10 patients
were not available
for review
because
of issues involving
patient
care but were reviewed
by experienced
radiologists
(L.E.G.,
W.R.N.,
D.M.Y.)
at the
institution
at which
they
were
obtained.
Studies
were
evaluated
for
(a) the presence
of intrasinus
high-attenu-
ation areas, (b) the extent
ment, (c) bone expansion
(d) bone
erosion,
and
disease
into
the
adjacent
of sinus involveand thinning,
(e) extension
of
soft
tissues.
cause
of the difficulty
in separating
vidual
ethmoid
on coronal
sinuses
opacification
least one sinus
(71)
(67)
43/45
(96)
44/45
(98)
43/44
(98)
42/44
(95)
41/44
(93)
of
Thinning
of sinus wall of
opacified
sinus
Involvement
32/45
30/45
of adjacent
soft-tissue
9/45
structures
Note.-Number
in parentheses
(20)
is the percent-
age.
RESULTS
ment
after surgery.
The
CT studies
were
correlated
with
surgical
and histopathobogic
reports
in all
patients.
Because
our study
was a retrospective,
multi-institutional
review,
the
imaging
techniques
varied.
All patients
coronal
sinus involvement
Expansion of opacified
sinus
Remodeling
of walls of
opacified sinus
did not undergo
comprehensive
testing
before
surgery.
This was
to the fact that the majority
of
before treatment.
The presence
of allergic
mucin
at endoscopy
was thought
to be
sufficient
evidence
for initiating
treat-
had
43/45 (96)
42/45 (93)
Complete
of
otolaryngobothe diagnosis
45/45 (100)
Frontal
Sphenoid
Multiple
(49)
23/45 (51)
intrasinus
attenuation
Involved
sinus
Ethmoid
Maxillary
allergic
fungab
sinusitis
(4). However,
an
in-depth
allergic
history
was not available in our series because
the majority
of
treated
by
not consider
22/45
Bilateral
Increased
a Gell and Coombs type I allergic
hypersensitivity
has been associated
with
patients
were
gists who did
45/45 (100)
Unilateral
atopyand
patients
allergic
related
Patients
Mucosal thickening
nab that has the consistency
of cottage
cheese. It is composed
of laminated
accumulations
of intact
and degenerating
eosinophibs,
Charcot-Leyden
crystals,
and
cellular debris (1). Finding
allergic mucin
at endoscopy
is thought
to be the sine
qua non for the diagnosis
of allergic fungal
sinusitis
(2,9).
presence
Fungal
CT Finding
was based
on criteria
established
by DeShazo
et al
(1). All patients
had characteristic
allergic
mucin
at endoscopy
and fungal
hyphae
identified
at light
microscopy.
Allergic
mucin is a brown
or greenish-black
mate-
The
of Allergic
Be-
mdiimages,
no attempt
was made
to determine
the
specific ethmoid
compartment
involved
by
disease. Thus, the anterior, middle, and postenor ethmoid
sinuses
were grouped
together as the ethmoid
sinus complex.
Clinical
Findings
Clinical
findings
in our series showed
that allergic
fungal
sinusitis
was more
common
in male patients.
Our results
are consistent
with
prior
reports that have suggested
a geographic
distribution
of allergic
fungal
sinusitis
(2,10,1 1). This series consisted
of cases
.
obtained
from
seven
academic
tions: four in the southeastern
western
and three
in the
and western
United
States.
of patients
from the southern
in warm and humid
climates
greater
than
the number
institu-
and southnortheastern
The number
institutions
(n = 3 1) was
from institutions in dryer climates
(n = 14).
The presenting
dinical
complaints
were
nonspecific
and consisted
mainly of symptoms of chronic
sinusitis.
Six patients
with
advanced disease also presented
with proptosis in addition
to chronic
sinusitis
owing
to
extension ofallergic ftmgal sinusitis into the
retrobulbar
region.
No patients
had meningitis or neu.rologic
symptoms
due to intracranial extension of disease.
CT
Findings
All of our patients
sinus
attenuation
opacificationonunenhanced
The mucosal
sinusitis
ethmoid
monly
had increased
intrawithin
the mucosal
thickening
studies
(Table).
in allergic
fungab
involved
any of the sinuses.
The
sinus
complex
was most
cominvolved,
with
at least
one eth-
Mukherji.t
al
diagnosis
should
be suspected
in atopic
patients
with
chronic,
often
intractable
sinusitis
and polyposis
(1). The similamities allergic
fungal
sinusitis
shares
with
allergic
bronchopulmonary
aspemgillosis
led to the first case report
by Safirstein
(12). Millam
et al (13) and
later
Katzenstein
et al (14) noted
characteristic
mucoid sinus
impactions
and nasal
polyposis in small groups
of patients
with chronic
sinusitis.
Histologic
evaluation
of that
mucoid
ing
a.
b.
Figure
1.
unenhanced
Allergic
fungal
sinusitis
with
CT scan shows
the typical
an expansile
ipsilateral
suggests
lesion
centered
ethmoid
that
this
neoplasm.
(b)
papyracea
sinus
mass
right
image
cavity
sinus
)c).
process
of a demonstrates
the roof of the maxillary
of the maxillary
sinus (large curved
structures
on the left (small straight
medial
wall of left maxillary
sinus).
involvement
of unilateral
maxillary
complex
(e) and nasal
is a benign
inflammatory
Bone-algorithm
(arrowhead),
in the
unilateral
appearance
arrow).
arrow
sinus
in a 25-year-old
allergic
fungal
antrum
expansion
Compare
this
=
contralateral
(A) that
The increased
rather
than
(small
and
curved
man.
(a) Coronal
sinusitis.
There
involves
intrasinus
a malignant
thinning
arrows),
with the normal
lamina
papyracea,
also
is
the
attenuation
sinonasal
of the
and the medial
lamina
wall
appearance
of the bony
large straight
arrows
attenuation
moid
suggest
sinus
allergic
complex
fungal
involved
sinusitis.
in 43 (96%)
of 45 patients.
This was followed
in frequency
of involvement
by the maxillary
sinus
(42 patients
[93%]),
the frontal
sinus (32 patients
[71%]),
and the sphenoid
sinus
(30 patients
[67%j).
Multiple
sinus involvement
was the mule: Only two
of the 45 patients
had disease
limited
to
Volume
207
Number
#{149}
2
these 44 patients,
43 (98%) had expansion
of the opacified
sinus, 42 (95%) had memodcling
of the
demonstrated
bony
sinus
walls,
and
41
(93%)
of a sinus wall.
Nine
(20%)
of
the
45 patients
had
evidence
of disease
extending
into adjacent
structures.
All nine
patients
had
bone
emosion:
Three
had intracmanial
disease extension,
three
had intraorbital
disease extension,
and three
had both
intmaorbital
and intracranial
disease
extension.
Of these
nine
patients,
six had bilateral
disease
and three
had unilateral
disease.
erosion
DISCUSSION
In the
allergic
span of only 2 decades,
fungal
sinusitis
has
revealed
hyphae
acute
thought
to be
brancha species
of the genus
Aspergillus.
Terms
such
as
“allergic
aspergillosis
of the pamanasal
sinuses”
and “allergic
aspergillus
sinusitis”
were initially
used to describe
the disease.
Later studies
that relied on actual
cultures
of fungi revealed
the role of dematiaceous
fungi
in the pathogenesis
of this disease,
prompting
Robson
et al (15) to coin
the
term
“allergic
fungal
sinusitis”
in 1989.
The most
common
fungi
are Curvularia,
Bipolaris,
Pseiida!lescheria,
Aspergillus,
and
Fiisariiun.
=
one sinus
(one
with
disease
in the ethmoid
sinus complex,
one with disease
in
the maxillary
sinus).
Twenty-two
(49%)
of 45 patients
had
unilateral
involvement,
with the right side
(n = 15) involved
more commonly
than the
left (ii = 7) (Fig 1). Twenty-three
(51%) of 45
patients
had bilateral
disease
(Figs 2, 3). Of
these 23 patients,
10 had symmetric
involvement and 13 had asymmetric
involvement.
Of the 13 patients
with asymmetric
involvement,
eight had disease
predominantly
on
the left side and five had disease
pmedominantly
on the right.
Forty-four
(98%) of 45 patients
had cornplete opacification
of at least one sinus. Of
Figure 2. Allergic fungal sinusitis
with bilateral
involvement
in a 39-year-old
man. Coronal unenhanced CT scan shows opacification
of the maxillary and ethmoid
sinuses. Erosion
of the larnina
papyracea
(arrowhead),
planum
sphenoidale
(white arrow),
and orbital
floor (black arrow)
could also be seen in a slowly growing
neoplasm.
However, the diffuse intrasinus
areas of increased
material
fungal
interest
in
grown.
This
Allergic
fungal
sinusitis
continues
to be
undemdiagnosed
because
it is often
not
recognized
as a distinct
clinical
entity
(3,7). In the past, allergic
fungal
sinusitis
has been grouped
under
the broad
classification
of “fungal
sinusitis”
rather
than
recognized
as a separate
disease
(5, 16, 1 7).
Recent
advances
have
led to a better
understanding
of fungal
sinus
infections
(1). Several
different
entities
are
now
thought
to compose
what
was
once
known
collectively
as “fungal
sinusitis”
(5). Fungal
sinus
disease
is now classified
as (a) allergic
fungal
sinusitis,
(b) sinus
mycetoma,
(c) acute
(fulminant)
invasive
sinusitis,
(d) chronic
invasive
fungal
sinusitis, and (e) gmanulomatous
invasive
fungal sinusitis
(1).
Allergic
fungal
sinusitis
may
constitute,
in part,
what
radiologists
have
mefemred
to in the past
as “superimposed
fungal
colonization”
of the sinuses.
Our
investigation
demonstrates
that
the CT
findings
that may suggest
a diagnosis
of
allergic
fungal
sinusitis
consist
of complete unilateral
or bilateral
opacification
of multiple
pamanasal
sinuses,
sinus expansion and erosion
of a wall of the involved
sinus,
and
scattered
intmasinus
highattenuation
areas amid
mucosal
thickening
on
unenhanced
Our CT
previously
CT
scans.
are similar
to those
by Manning
et al
(2).
Because
our
study
is a retrospective
one in which
we evaluated
known
cases
of allergic
fungal
sinusitis,
we cannot
conclude
that
the imaging
findings
are
“highly
(2).
findings
described
specific,”
However,
as previously
our
CT of Allergic
findings
Fungal
suggested
suggest
Sinusitis
that
419
#{149}
the presence
of a unilaterally
opacified
sinus
associated
with
sinus
expansion,
bone
remodeling,
and
increased
internal attenuation
on unenhanced
CT scans
should
raise
the
possibility
of allergic
sinusitis
from
these
latter
two
disease
entities.
Our findings
reinforce
the need to look
at soft-tissue-algorithm
images
when
performing
CT in patients
with chronic
sinus-
fungal
itis, because
the
of increased
fied at these
attenuation
settings.
sinusitis.
sinus involvement
also is common
and
present
in patients
with
advanced
disease.
Patients
with
advanced
Bilateral
bilateral
involvement
are more
likely
to
have
intracranial
or intraorbital
extension
of disease
at the
initial
imaging
evaluation
than
are patients
with unilateral disease
(Fig 3). The degree
of bone
erosion
and
extension
beyond
a sinus
may
mimic
aggressive
sinonasal
neoplasms.
The presence
of increased
internab attenuation
on unenhanced
CT scans
may
help
to distinguish
allergic
fungal
sinusitis
from the more common
sinonasal tumor
(Fig 3) (5,17).
It is conceivable
that rare sinonasal
meningiomas
or sarcomas that produce
a chondroid
or osteoid
matrix
could
contain
high-attenuation
areas and may mimic
allergic
fungal
sinusitis on unenhanced
CT scans.
It also is
possible
that CT may not be able to help
distinguish
allergic
fungal
sinusitis
from
desiccated
secretions
within
mucoceles
or polyps.
However,
the presence
of cxpansion
and thinning
of the sinus
walls
may help separate
allergic
fungal
sinusitis
from
chronic
disease
with
desiccated
secretions,
which
often
results
in thickening and
sclerosis
of the adjacent
sinus
walls (Fig 4).
Our results
suggest
that
CT may help
identify
patients
with
allergic
fungal
sinusitis
and
may
differentiate
this from
other
forms
of fungal
sinusitis.
The CT
finding
of mycetoma
is a focal round
area
of increased
attenuation
that
is usually
centered
within
a diseased
maxillary
sinus (1,16,17).
Conversely,
allergic
fungal
sinusitis typically
involves
multiple
sinuses,
expands
the involved
sinus,
and is
associated
with
diffuse
scattered
intrasinus areas of increased
attenuation.
Acute
invasive
fungal
sinusitis
is characterized
by aggressive
bone
erosion
with
extension
of disease
into
the
adjacent
soft
tissues
(16-18).
Infection
arising
in the
maxillary
sinus may spread
anteriorly
into
the canine
fossa
or posteriorly
into
the
pterygopalatine
fossa
(19).
It is uncommon for acute
invasive
fungal
sinusitis
to
expand
a sinus
or remodel
a sinus
wall.
Intrasinus
high-attenuation
areas
at CT
are unusual
in acute invasive
fungab sinusitis
(17,18).
The
imaging
findings
of
granulomatous
and chronic
invasive
fungal sinusitis
have
not
been
clearly
defined.
Thus,
it is unclear
whether
CT can
be used
to differentiate
allergic
fungal
420
Radiology
#{149}
May
#{149}
1998
internal
intrasinus
areas
are best identiThe high
attenua-
tion
in allergic
fungal
sinusitis
is likely
due to a combination
of heavy
metals
(iron
and manganese),
calcium,
and inspissated
secretions
that are often
found
in fungal
elements
(5,16,17,20).
Our
study
is a retrospective
analysis
in
which
we evaluated
the CT findings
of
documented
cases of allergic
fungal
sinusitis.
Because
we did
not
compare
the
imaging
of allergic
fungal
sinusitis
with
that of sinonasal
polyposis
or with that of
mucoceles,
we are unable
to comment
on
the
predictive
value
of our
findings
(2,3,4,11,21,22).
Thus,
even though
ablergic fungal
sinusitis
may be suggested,
it
may
not
be
possible
to differentiate
aller-
gic fungal
sinusitis
from advanced
sinonasal polyposis
or mucoceles
that also contam
multiple
mycetomas
or desiccated
secretions
(Figs 2, 4). It is probable
that
early cases of allergic
fungal
sinusitis
with
only
partial
opacification
of the sinuses
may
be
indistinguishable
other
ening
nonfungal
seen
in
similar
nonspecific
from
types
patients
of mucosal
presenting
cases
Advanced
allergic
fungal
aggressive
sinonasal
man.
Unenhanced
sinusitis
neoplasm
coronal
CT
scan demonstrates
an aggressive
sinonasal
mass
that erodes the lamina papyracea
and invades
the
orbits
(straight
arrows).
The
mass
also
erodes the skull base and extends
intracranially
(curved arrow). The presence
of the intrasinus
area of increased
attenuation
suggests a benign
inflammatory
process.
of
symptoms.
allergic
mucin
(2,6,22).
Magnetic
resonance
(MR) imaging
does
not appear
to play a substantial
role in
the
initial
diagnosis
of allergic
fungal
The
3.
mimicking
an
in a 45-year-old
thickwith
Common
spread
patterns
in advanced
allergic
fungal
sinusitis
included
intraorbital extension
through
the lamina
papymacca and intracranial
extension
by means
of erosion
of the sphenoid
sinus,
planum
sphenoidale,
and
posterior
wall
of the
frontal
sinus
(Figs 1, 3). The bone
expansion
and
thinning
typically
associated
with allergic
fungal
sinusitis
is likely due
to pressure
from
a combination
of the
underlying
sinonasal
polyposis
and the
sinusitis.
Figure
signal
contents
reported
itis is likely
due
intensity
loss
in allergic
fungal
to a combination
in sinus
sinusof an
absence
of freely mobile
protons
and the
presence
of heavy
metals
within
dense
fungal
concretions.
The concomitant
susceptibility
effects
that lower signal
intensity on T2-weighted
MR images
are not
specific
to allergic
fungal
sinusitis
and
could
result in the underestimation
of the
extent
of sinus
involvement
at MR imaging (16,17)
(Fig 5).
As additional
information
has accumulated,
it has become
increasingly
apparent
that
allergic
fungal
sinusitis
repre-
.*1
-‘
Figure
4. Diffuse sinonasal
ing allergic
fungal
sinusitis
man.
Coronal
unenhanced
complete
opacification
polyposis
mimick-
in a 28-year-old
CT scan
shows
of the
maxillary
and
ethmoid
sinuses.
Theme are intrasinus
areas
of
high
attenuation
similar
to those
in Figure
2.
Note the thickening
of the walls of the maxillary sinus
(arrows).
This thickening
was confirmed
on bone-algorithm
scans.
Endoscopy
showed
diffuse
evidence
were identified
sents
sinonasal
of allergic
an
mucin.
at histologic
polyposis
without
No
hyphae
fungal
evaluation.
rather
than
an
Although
the exact
pathophysiology
remains
a matter
of conjecture,
it is postulated
that
the pathophysiology
of allergic
fungab
sinusitis
is
similar
to that of allergic
bronchopulmonary aspergillosis,
involving
both
immediate
and
delayed
hypersensitivity
(3).
infectious,
immunologic,
disorder.
Mukherji
et al
a.
b.
c.
(a, b) CT scans and (c) MR image of allergic fungal sinusitis
in a 38-year-old
man. (a) Axial unenhanced
bone-algorithm
CT scan shows an
expansile
mass that involves
the ethmoid
and sphenoid
sinuses. The diffuse erosion of the walls of the sphenoid
sinus (arrows) suggests a neoplasm.
(b) Soft-tissue-algorithm
unenhanced
CT scan shows diffuse intrasinus
areas of increased
attenuation.
This finding
favors a diagnosis
of allergic
Figure
5.
fungal
sinusitis
over
a diagnosis
of
sinonasal
neoplasm.
(c)
Axial
T2-weighted
MR
image
(3,000/90
(repetition
time
msec/echo
demonstrates
diffuse areas of signal intensity
loss within the sphenoid
and right ethmoid
sinuses.
underestimated
in c as opposed
to that in a or b. The signal intensity
loss is likely due to a combination
presence
of heavy metals within fungal concretions.
Note how the extent of disease
of an absence of freely mobile
Patients
with
allergic
fungal
sinusitis
often have allergic
rhinitis,
asthma,
eosinophilia,
and elevated
total and fungus-specific immunoglobulin
E concentrations
(1).
These associated
findings
are best diagnosed
by means
of allergic
testing,
which
includes
skin
and
radioabbergosorbent
testing
(1).
However,
these findings
may not always
be
identified
in patients
with
allergic
fungal
sinusitis
(6). This may be rebated to the fact
that
a majority
of patients
are treated
by
otolaryngologists
who do not consider
the
diagnosis
before
treatment.
Thus,
in-depth
presurgical
allergy
testing
is often
not performed
during the examination
of these
patients.
Manning
et al (23) suggest
that several
related
factors
are necessary
for the development
of allergic
fungal
sinusitis.
Initially, an atopic
individual
inhales
fungi,
which
come
to rest within
a paranasal
sinus. The presence
of this
fungal
antigenic
stimulus
incites
a Gel and Coombs
type I (immunoglobulmn
E-mediated)
and
type III (immune-compbex-mediated)
inflammatory
response,
resulting
in obstruction
of a sinus
ostium
and
mucostasis
within
that
paranasab
sinus.
Within
this
environment,
the inciting
fungus
continues to proliferate,
further
exacerbating
immunologically
mediated
inflammation. Eventually,
eosinophilic
allergic
mucm,
in combination
with
proliferating
fungal hyphae
and polyposis,
give rise to
an expanding
sinus,
yielding
the characteristic
clinical
picture
of allergic
fungal
variety
Volume
207
Number
#{149}
2
sinusitis.
Thus,
the treatment
of allergic
fungal
sinusitis
differs
from other
types of
fungal
sinusitis
and consists
of the oral or
topical
administration
of prednisone
after surgical
d#{233}bridement.
The suggested
therapy
is a 4-week
course
of oral prednisone
followed
by a long-term
course
of
short-acting
intranasal
corticosteroids
(1,7).
Recent
study
findings
suggest
that
allergen
immunotherapy
to downregubate the production
of fungus-specific
immunoglobulmn
E and decrease
the inflammatory
reaction
may
also be beneficial
(1,4).
Preoperative
CT findings
that
suggest
allergic
fungal
sinusitis
may
facilitate
ob-
taming
the necessary
laboratory
studies
required
to establish
the diagnosis.
Every
attempt
should
be made
to fulfill
the
diagnostic
criteria
of allergic
fungal
sinusitis before
the initiation
of steroid
therapy
because
of its inherent
side effects
(21).
This
is especially
important
given
the
preponderance
of allergic
fungal
sinusitis
in the pediatric
population,
as reported
by others
(21). The presence
of CharcotLeyden
crystals
within
the tenacious
mucm will help corroborate
the diagnosis
of
allergic fungal
sinusitis
(7,22).
Suspicion
of allergic
fungal
sinusitis
alerts
the pathologist
to evaluate
the histopathologic
specimen
specifically
for this histologic
marker.
Special
fungab
stains
may be necessary
to identify
fungal
hyphae
that may
not be seen with standard
hematoxybineosin
staining
(3,9,24).
Because
of
the
isms
and
that
time
fastidiousness
may
of
be present
gal sinusitis,
special
required
for growing
msecj)
is substantially
protons
and the
the
organ-
in allergic
culture
the
media
specific
funmay be
fungal
species
(3,6).
In summary,
allergic
fungal
sinusitis,
a
distinct
clinical
entity
with
nonspecific
symptoms,
may be initially
suggested
by
the CT findings.
Our results
are consistent
with
those
of smaller
series
and
suggest
that the diagnosis
of allergic
fungal sinusitis
may be indicated
by certain
findings
at CT (2,7,8,25,26).
When
present, these
findings
should
alert the clinician
to the possibility
of allergic
fungal
sinusitis
and prompt
the referring
physician to perform
the other
studies
necessary to establish
the diagnosis
and plan
treatment
(2,4,7,11,22).
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